Table 1. Summary of results from the GLMM explaining the number of fledglings in female storks (n = 111 breeding attempts).

Effect	Estimate	SE	F-value (df)	P
intercept	1.044	0.505	2.07a (5)	0.093
age	−0.222	0.117	0.32 (1,49)	0.574
group	−1.444b	0.863	2.80 (1,49)	0.101
age×group	0.351b	0.163	4.64 (1,49)	0.036
bird	0.117c	0.129
year of birth	0.018c	0.076
year of breeding	0.049c	0.078

Number of fledglings was the response variable. Group (hatched before or after the spill) and female age were explanatory variables, and bird, year of birth (cohort) and year of breeding were treated as random effects. SE, standard error; df, degrees of freedom;

^a t-Test;

^bEstimate corresponds to the group of storks hatched before the spill (the level “hatched after the spill” is aliased);

^crandom effect. The estimated effects, SE, F-values and associated probabilities are shown for those variables that significantly improved the fit of the model (χ²/df = 1.06).